AW: opamp compensation in integrator application (was:Re: Descret OTA )

[terry michaels]

Message text written by Haible Juergen
>Hi Terry,

that's pretty much how I see it, too. Make the opamp as fast as possible,
and care
for stability by increasing the noise gain. 
But what if they would have compensated the 301 (i.e. made it slower) for
unity gain
stability, and then built a "normal" integrator around it (without the cap
to ground) ?
My "feeling" says it would be an inferior solution, but I haven't done the
calculations
to back it up. Would you say that the difference is still neglegible,
because of the
overall integrator function ?

JH.
<

Hi Juergen:

With normal compensation, and no cap to ground, the overall performance of
the circuit would be inferior for the following reasons:
1.  You could have slew rate limitations at the upper part of the audio
band when there is a large signal swing.
2.  Distortion will increase, especially at higher frequencies, because the
open loop gain is reduced, so there is less gain to counter the inherent
non-linearity of the opamp transfer characteristic.  Gain error will
increase.
3.  Transient response is poorer.

Whoever designed the ARP circuit knew what he was doing, he got good
performance out of a poor (by todays standards) opamp.

Terry Michaels